How to calculate the gas cost of a trip

It’s easy to jump in the car and just drive, but when you’re taking a road trip, or even starting a new commute, a little planning goes a long way. Calculating the gas cost of a trip is a smart trick to budget travel expenses, and there are a couple of routes you can take. One is doing it by hand, which can be completed in a few simple steps and gives you some useful know-how, while the other is using an online gas cost calculator. For that, you’ll need a few basic details about your car.

Route A – Take 4 simple steps

1. Calculate your miles per gallon

Fill up your gas tank and set the trip odometer button on the instrument panel to zero, then drive normally until it’s time to stop for gas again. When you next refuel, note the trip odometer reading to get the number of miles you’ve driven. Alternatively, you can get this figure by writing down the overall odometer reading the first time you fill up and again the second time, with the difference being your miles driven. Next, divide the mileage by the number of gallons of fuel you pumped on the second gas stop to get your miles per gallon.

2. Work out the trip distance

Whether you’re going point-to-point or taking a round trip, a quick look at resources such as Google Maps or your phone’s navigation app will tell how many miles the journey will be. This is a good time to select your preferred route, consider traffic hot spots to avoid and, if you’re planning a road trip, think about any sights and detours you want to build into the trip.

3. Get the price of gas

You may remember the price of gas from your last fill up but prices can fluctuate a lot over time and by region, so that may not be a good guide. Have a look at the current national and regional gas prices provided by the AAA to get an idea of what the price of gas will be for your journey.

4. Calculate the overall gas cost of your trip

With miles per gallon, trip distance and the price of gas at your fingertips, you can calculate the gas cost of a trip with a simple formula. First, divide the distance of the route by your miles per gallon figure to find out how many gallons of gas you will need. After that, multiply the number of gallons by the price of gas to calculate the gas cost for your journey.

Route B – Use an online calculator

There are a number of useful calculators that will give you the cost of a trip and even directions and information for savings on gas. The government’s fuel economy website enables you to select your vehicle year, make, model and engine type, enter your start and finish points and any stopping off places on the way, plus the percentage of city driving for the trip. Click to calculate and you’ll receive your fuel cost estimate, a map of the journey and directions. You can also enter additional vehicles to compare costs.

GasBuddy is another good option that’s slightly different. Type in your starting location, a stop-off if you have one, destination, and select whether you want to calculate a one-way or round trip. Then select your car’s year, make, model and engine type, along with the fuel you use – regular, midgrade, premium or diesel. Tap “calculate” and GasBuddy will provide the trip cost, distance and projected gallons used, as well as where to fill up and your potential savings from using recommended gas stations.

Other road trip expenses

Whichever way you go about it, calculating the gas cost of a trip is a useful means for planning ahead and, while it is more a guide than an exact figure, it will help you avoid an unexpected fuel bill at the end. Remember that unforeseen circumstances can crop up from time to time, such as accidents, detours and delays, which might add miles and gas onto your journey. And, on a long trip, there are normally other expenses to consider, such as stops for food and drink, toll fees, and the need to pull in when you see that “best ice cream in the world” sign.